Process of preserving hard wood.



A. F. BARRY. PROCESS 0F PRESBRVING HARD Woon. APPL-NATION I'IL'ED JUNE 29, 1907.

1,006,713. Patented oct. 24, 19411.

UNITED STATES PATENT @FETCH- vnous r. Bannion KANsascrrY, MISSOURI. t

PROCESS' 0F `'.EIRESlillltVING' HARD WOOD.

Specification of Letters Patent.

Application led- .Tune 2,9, 1907. Serial No. 381,538.

v a process of saturating and preserving hardwoods, such as oak, gum and like varieties of timber, and in which the sap and moisture within the sap channels resist the pene! tration ofa preservative, and-it has for its object the elimination of the moisture and the complete penetration of the preservative.

vThe accompanying drawing shows, in perspective, the form kof apparat-us with which my process may be performed.

The hardwood to be treated is stacked upon a flat bottom car 1, mounted upon the track rails 2, terminating adjacent to the door 3, of an air-tight cylinder or retort 1, which retort is of suitable dimensions to admit of the reception of a large quantity of lumber for treatment. The hinged door 3, closing one end of the cylinder being opened, the car with its load of lumber is moved within Vthe retort upon the track rails 5, in the bottom'v of the retort, and the door closed and secured by the clamping.

bolts,'hermetically sealing the retort.

In the preliminary steps of my process the hardwood within the retort is subjected to a process of sweating, in which process radiant heat is employed, emanating from a series of steam-circulating chambers 6, located in the upper portion or top of the retort, to which dry steam'is admitted :from a steam supply pipe 7, supplying steam from any suitable source through branch pipes 8. This supply of steam is regulated Vand cutfof by a valve 9, in the steam-conducting pipe 7, the steam escapes through the separate pipes 10, and through the interlcommunicating discharge pipes l2, to pipe 13, controlled by the exhaust valve 14. The air within the top of the retort/is heated by the steam to approximately 115 Fahrenheit.' The heated air, to produce the sweat` ing of the hardwood, originates and is drawn downward through the wood charge from the top of the chamber or retort, in

order to' produce the results which are the novel feature of my invention, and-.which will be disclosed intheI steps employed.

When the air in the retort ory chamber-becomes heated to the de rees stated, the exhaust valve 17 is partially'open'ed, and'a f Patented 2.14, t911. 'i

descript-,ionf'ot the" suction is produced within the' retortA upon the air, graduallyb'fby the suction pump-15,V which has4 an inductionpipey 16"'connec`ted with' the lower portion 4ofV theretort, and at' a point intermediate the' ends ot said rtort, the `action of thel suction' pump lually creating a'vacuum within thel retort sufficient to distribute the heated air andl4 moisture evaporated from the wood throughout the retort, and drawing theheatedai'r vand moisture downwardly through the wood, which'lies horizontally upon 'the' car,

causing the lumber to sweat rapidly and release the' sap from Athe sap-channels, and

the saps are removed throu'ghthe pores of the wood, leaving the sapchannels`fully open.

gradually increased during the action of the The opening of the exhaust valve 17 Y is" suction punrp,- producing the vacuum. `The` sap and moisture now being gradually eliminated from the wood .are removed byn'thert suction pump from the retort.l The sweating of the-hardwood, andthe elimination of thesaps and moisture, and 'the .withdrawal of same fromthe retort as fast as produced,

prevents an accumulation of liquids by condensa-tion in the bottomof the'4 retort, and

also prevents the saturation of the wood charge by re-absorption ofthe liquid.

The sweating process opens up" the sap channels and exhausts all the moisture, and the glutinous scale which has formed on the walls has time to vaporize-and-pass out in. a

volatile condition, with the 'sap,allowing the preservative A(when applied later Lon) to enter the lumber.- A quicklhigh vacuum,vv

with high temperature, would crystallize the .gums and would prevent thorough drying of the lumber, and also would lcause check-v ing.

It will be observed thatthe vacuum isnot i produced rapidly by l a strong suction'. n

Upon the other hand, a slow and progressively increasing vacuunr'fis employed, so as to gradually increase the volume of heated air, drawn from the top of the retort. The

heated air is drawn downward' by the suc-` tion of the pump throughv the wood charge -to produce a humid atmosphere within the iretort.' The moisture inthev bottom of the sap wood "moisture, than does' the heart-wood. The vvheated air is therefore controlled in volume, accordingA to the condition of the charge within the retort,'by a suction of greater or less force upon the heated air in thev top of the retort. vUponthe completion of the sweating of the hardwood, which is ascertained by the cessation of the fiow`of fluid from the suc- 'tion pump, the steam 4is cut o from chambers6 and the vacuum in the retort is in-V creased by the suction pump to twenty-five inches or more, which vacuum 1s held approxirn'atelyV forty or'ifty minutes, simultalneously drawing 0H any fog that may remainl from' evaporation 'of time the valve 17, is closed. Creosote Fahrenheit, is then thewood, after which leading to the pump 15, oil, at about 190 to 200 introduced into the retort, under pressure -portion of the retort by through the pipe 18, leading into the upper opening of valve 20. The hot oil enters the retort with rapidity, destroying the vacuum and lling the retortcompletely. Pressure is then further applied to the oil within t-he retort, to produce a. pressure of 140 or more pounds. .The pressure ofthe oil within the retort 1s indl-y ycated by the gage 1 9.

y Upon sufficient penetration of the preserva'ti'veinto the. wood, the valve 20, in the pipe 18, is closed. Suitable check valves 21 and 22, on the separate. pipes or conductors 23 and 24:, leading from the compressed a1r storage and cooling tank 25 to the end of the retort, are then openedto admit'the compressed 'air cooled by expansion to a temperature of 30 to 60 Fahrenheit, into there- "tort, at a. pressure of approximately eighty .to one hundred pounds per square inch, indicated by the gage 28. lThe outlet valve 26, in the discharge pipe 27, at thelother end of the retort', is then opened to a `small extent,

to reduce theY pressure now on the oil, of 140 pounds or. more, until the pressure of the oil on the valves 21 and 22, and the air-pressure becomes equalized and is maintained. The retort being filled lcompletely with oil, and the discharge of the oil under pressure, through. outlet valve v26, at'80 to 100 pounds pressure the air enters through valves 21 and 22, at an equal pressure .of 8O to 100 pounds. Upon the decrease of volume Aof the oil body, caused by the discharge through the outlet valve 26,'the pressure of the cooled, compressed air from the end of the retort on the oill forces the oil body in the direction the moisture from of valve 26, whichfis opened suiiicientlyto permit the oil to be discharged in a restricted quantity, while still holding the air pressure at S0 lto 100 pounds upon the hot oil within the retort, this pressure being indicated by the gages 19 and 28. The wood e charge ybeing placed longitudinally, upon the air and the volume of the oil body being decreased and the volumel of the cooled, compressed air being increased, thewood is cooled and contracted; also the oil is made viscid in the sap channels, by the cool, compressed air, as it passes through the wood charge and toward the outlet valve 26.

The hot oil expands the wood and penetrates the sap channels the full length of the timber, and then the cold compressed air, cools and contracts the wood and sap channels, and also makes the oil preservative viscid within the sap channels. The hot oil and cold air, respectively, heat and cool the wood equally, so that the fiber structure is not injured or disturbed, and the sap channels are sealed by the preservative so that before exposure to the atmosphere the lumber is cooled and is not checked. This cooling within the retort'saves time and expense, the wood being fully treated, any excess oil is vblown out by the air by fully opening outlet valve 26, the cool air passing, driesy the wood in thefretort.

At the completion of the process, ,the

valves 21, 22 are closed. The door 3, to the retort, is opened, and the preserved lumber removed from the retort. l The results of my process are: The viscosity of the oil eft'ectively prevents breaking down of the walls of the sap channels, a thorough penetration of the hardwood lumber is obtained, thus increasing the longevity of the hardwood. In

`my process the lumber is preserved Without reducing its former tensile strength, and being in a treated condition, fungus growth is prevented, and will better resist rot .and decay. vThe lumber is firm, and the oil in a viscous condition, not beingvolatile by heat prevents oozing when taken from the retort.

Having fully described my invention, what I now claim vas new and desire to secure by `Letters Patent is:

1. The -herein described process of preserving hardwood, consisting in heating the air above the wood being treated in a retort, applying suction at the bottom ofl the retort to create a vacuum, thereby drawing off the heated air and moisture gradually from the bottom of the retort downwardly ,through the hardwood to cause sweating of the woodfthen subjecting the wood to hot` preserving oil under pressure thereby destroyng the vacuum, then allowing the pressure to drop somewhat by alloviring, oilv to escapey from the retort, then admitting-compressed air under -expansion andat alow temperature tne .end of. the retort in conserving hardvvood, consisting in heating the air above the Wood being treated Within a retort, applying. suction at the bottom oftheA retort to create ajvacuum Within the retort and to drawthe heated air and moisture evaporated from the Wood downwardlyA through the Wood gradually and cause sweating ofthe Wood, increasing the suction and vacuum to remove the remaining moisture inthe Wood, and then' introducing hot preserving oil under pressure, and then admittlng compressed air cooled by expansion to a 10W temperature to one end of the reltort while allowing the unabsorbed oil to flow veiy gradually from the bottom of the retort, whereby the cold compressed air in conjunction Wit-h the hot oil displaces the hot oil gradually from the Wood, thereby contracting the Wood and viseidifying the preservative in the' sap channels by the cold compressed air.

l ANGUS F. BARRY.4 Witnesses:

JENNIE SAMPsoN, A. C. STownLL. 

